I am trying to install an Arduino Leonardo under Win8.1. A couple of days ago I successfully did this using a “compliant” driver that win found during the driver install dialog. I was able to upload and run sketches from the arduino ide. I attempted to do the same using Atmel Studio 6.2 with the Arduino plugin. That didn't work. Today, I tried using the Arduino IDE unsuccessfully. I get the “driver disappearing behavior” described in other forum posts. Only, in my case it really does disappear. The driver in NOWHERE in the device manager. If I reset the leonardo or re plug in the usb connection, the Device Manager shows first the “Leonardo Boot Loader” and then the “Leonardo driver” (Like other posts have described). If I wait, it disappears. If I'm really fast and get into the install dialog, it finds the correct driver and then tells me that the best one is already installed. When I exit the dialog, the Leonardo entry in the device Manager is gone.
I have read relevant posts, tried the signature work around and I am completely out of ideas.
The last day or so I've tried to install the 64 bit driver in the the arduino/driver folder with the results described above. The only thing that has worked (briefly) was the “compliant” driver win found(but no longer). Worst of all, the problem is intermittent; both the arduino IDE and Amtel Studio 6.2 have worked now and then for several hours. Now, not so much (actually, in the last hour, not at all).
This thing is driving me bonkers. Help!